MRSO: EXAM QUESTION AND CORRECT ANSWER 100% A+

MRSO: EXAM QUESTION AND CORRECT ANSWER 100% A+ Peripheral nerve stimulation can be described by which of the following? a. Faraday's law of induction b. Ohm's law c. Lenz's law d. Planks Law - CORRECT ANSWER-b. Faraday's law of induction (describes the induction of electrical current in the presence of a changing magnetic field). Lenz's force describes the opposing forces created. Ohm's law deals with the resistance of current along a wire. Gad contrast has been found in the body in what form? Select all that apply. a. Water-soluble b. Non-water soluble - CORRECT ANSWER-a, b Which of the following would we expect to be the loudest sequence? a. GRASS b. Fast spin echo c. Conventional gradient sequence d. FLAIR - CORRECT ANSWER-a. GRASS The FLAIR and fast spin echo are considered spin echo sequences; they do not have extremely fast changing gradient, so will not produce as much noise. Which of the following has a steeper spatial magnetic gradient? a. Vertical B0 b. Horizontal B0 - CORRECT ANSWER-a. Vertical B0 The strongest gradient strength will reach maximum strength how far from isocenter? a. 5-20 cm b. 20-40 cm c. 30-60 cm d. 5-15 cm - CORRECT ANSWER-c. 30-60 cm Which of the following is true of gad and breastfeeding mothers? Select all that apply. a. Gad is found in breast milk in a stable and chelated form b. It is thought that gad contrast may alter the taste of breastmilk. c. Available data suggests that breastmilk should be pumped and discarded for 24 hours after the IV dose d. 20% of the intravascular dose would be excreted into the breastmilk within the first 24 hours. - CORRECT ANSWER-a, b Which of the following will influence peripheral nerve stimulation? a. Static magnetic field b. Magnetic field at isocenter c. Patient weight d. Slew rate - CORRECT ANSWER-d. Slew rate Which of the following pulse sequences would we expect to see the least patient heating? a. Incoherent gradient b. STIR c. Fast spin echo d. EPI - CORRECT ANSWER-d. EPI A patient comes in with a 1 cm brain aneurysm clip and you find the package which lists what metal it is made from. Which of the following metals would make it unsafe to scan this patient? a. Elgiloy b. Phynox c. MP35N d. 405 Stainless steel - CORRECT ANSWER-d. 405 Stainless steel Phynox, elgiloy, titanium, and 316 stainless steel are non-ferrous. 17-7PH and 405 stainless steel are ferrous Which of the following are true of Lenz's force? a. Occurs because of the interaction between a ferrous object and the static magnetic field b. Influences objects that are electrically conductive c. Influence on an object depends on the field strength d. Increases with the rate of motion through the static magnetic field. - CORRECT ANSWER-b, c, d Lenz's law is caused when an electrically conductive object (not ferrous) interacts with a strong magnetic field. The speed that the object translates through the magnetic field as well as its dimensions, orientation, and the overall magnetic field will influence the amount of Lenz's force on an object. This force acts as a repulsive force when translating through the static magnetic field. A patient is having an MR lumbar spine in normal mode. We know that the SAR will not exceed which of the following? a. 4 W/kg b. 3 W/kg c. 2 W/kg d. 1 W/kg - CORRECT ANSWER-c. 2 W/kg An MR conditional implant should minimally address which of the following? Select all that apply. a. Switched gradient magnetic fields b. Patient position c. Radiofrequency fields d. Static magnetic field - CORRECT ANSWER-a, c, d Where would we expect to see hotspots? a. Areas in the near field b. Areas with low dielectric constants c. Areas under the transmit RF coil d. All the choices are correct - CORRECT ANSWER-d. All the choices are correct There is a large number of literature that suggests that patients in sickle cell crisis who receive gad contrast can develop many complications, even death. a. True b. False - CORRECT ANSWER-b. False Which of the following slew rates would produce the greatest chance for peripheral nerve stimulation? a. 180 T/m/s b. 200 T/m/s c. 100 T/m/s d. 125 T/m/s - CORRECT ANSWER-b. 200 T/m/s The ICNIRP sets and occupational dose of _______ to the head and torso. a. Spatial peak magnetic flux density of 6T b. Spatial peak magnetic flux density of 4T c. Spatial peak magnetic flux density of 2T d. Spatial peak magnetic flux density of 1T - CORRECT ANSWER-c. Spatial peak magnetic flux density of 2T A patient is having MR pelvis exam. Where would we expect the patient to experience peripheral nerve stimulation? a. Head b. Legs c. Groin d. Feet - CORRECT ANSWER-b. Legs The amount of patient heating depends on which of the following? a. Surface area b. Receiver coil c. Patient mass d. Controlled operation - CORRECT ANSWER-a, b, c, d Which of the following will demonstrate translational force? Select all that apply. a. A titanium hip replacement b. A steel aneurysm clip c. A cobalt heart stent d. Gad contrast - CORRECT ANSWER-b. A steel aneurysm clip Cobalt, titanium and gad are non-ferrous. They will not demonstrate translational force. Steel is and will translate and rotate in the presence of a static magnetic field. Which of the following are bioeffects associated with the time-varying gradient magnetic field? Select all that apply. a. Peripheral nerve stimulation b. Heating c. Magnetohydrodynamic effect d. Magnetophosphenes - CORRECT ANSWER-a, d There's been no evidence of heating associated with the time-varying gradient fields. Magnetophosphenes and peripheral nerve stimulation have to do with a fast changing magnetic field. We find this with the time-varying gradient field. Magnetohydrodynamic effect has to do with the static magnetic field and flow potential. Which of the following is true of a 3T MRI? Select all that apply. a. It will produce more stimulation at isocenter than other field strengths. b. Will have a larger maximum spatial gradient than a 1.0 T unit c. It will have a higher whole body SAR limit in normal mode than the normal mode at a 1.5 T d. Have more chance for peripheral nerve stimulation than at 1.5T - CORRECT ANSWER-b. Will have larger maximum spatial gradient than a 1.0 T unit. Passive metallic implants <2cm are not expected to heat up during image acquisition. a. True b. False - CORRECT ANSWER-a. True The strength of the gradient field will reach a maximum strength of what? a. 10-30 mT b. 40-60 mT c. 20-40 mT d. 0-20 mT - CORRECT ANSWER-c. 20-40 mT (0.04 T = 40 mT) Which of the following describes the translational magnetic field demonstrated to a patient at a specific location? a. dB/dt b. dB/dx c. dB/dt*B - CORRECT ANSWER-b. dB/dx The static magnetic limit for the general public for any body part is set to what? a. 4T b. 400 mT c. 2T d. 200 mT - CORRECT ANSWER-b. 400 mT (0.4T) The quench vent outside the MR facility is inspected by whom? a. MR tech b. Manufacturer engineer c. Facility engineer d. MRMD - CORRECT ANSWER-c. Facility engineer (The quench vent in the MR room is inspected by the manufacturer engineer) What type of gad contrast has been shown to cause falsely low serum calcium laboratory values? a. Linear ionic b. Linear non-ionic c. Macrocyclic d. There is no correlation - CORRECT ANSWER-b. Linear non-ionic Pregnant patient should never receive contrast. a. True b. False - CORRECT ANSWER-b. False We are scanning a cardiac MRI. What body part would we expect to experience peripheral nerve stimulation? a. Knee b. Foot c. Heart d. Head - CORRECT ANSWER-d. Head To date, most mechanical valves are unsafe at field strength of 3.0 T. a. True b. False - CORRECT ANSWER-b. False All tested heart valves are conditional at field strengths of 4.7 T or less Where would you expect to see the most heating on the IVC filter? a. the end of the wires b. the middle of the wires c. at the top of the filter - CORRECT ANSWER-a. the end of the wires (smallest diameter)